Tumors shed their cells into the peripheral blood, generating metastases that confer their lethality. Circulating tumor cells (CTCs) have been detected in patients of many types of cancers, even those with no signs of clinically overt metastases. Because CTCs are accessible using minimally invasive procedures, the detection and characterization of CTCs are pivotal for early diagnosis, prognosis, and treatment monitoring, as well as for understanding of the molecular and cellular events that lead to metastases. Our objective is to establish a sensitive and reliable method for detecting and capturing CTCs of all tumor types, regardless of their tissue origins, in research and clinical settings. We hypothesize that the telomerase-selective adenoviruses specifically label cancer cells and provide a simple method for efficient CTC detection and isolation. Our specific aims are (1) to generate replication-competent adenoviral vectors with optimized hTERT promoters for selective labeling of viable cancer cells; (2) to generate and characterize a tet-regulatable telomerase-selective adenovirus for the detection and isolation of viable CTCs. PUBLIC HEALTH RELEVANCE: Circulating tumor cells are clinically relevant for early detection of primary cancers, evaluation of treatment responses, and as a prognostic indicator on primary cancer recurrence and metastasis. In this application, we plan to develop a new generation of recombinant adenoviral imaging systems for detection and isolation of telomerase-positive circulating tumor cells.